
Installation Guide
English – May 2002
168 Series
Introduction
This installation guide provides instructions for installation, startup,
and adjustment. To receive a copy of the instruction manual,
contact your local Fisher Sales
Office or Sales Representative or view a copy at
www.FISHERregulators.com. For further information refer to:
168 Series Instruction Manual, form 2256, D100275X012.
P.E.D. Categories
This product may be used as a safety accessory with pressure
equipment in the following Pressure Equipment Directive 97/23/EC
categories. It may also be used outside of the Pressure Equipment
Directive using sound engineering practice (SEP) per table below.
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Specifications
Maximum Allowable Pressures
Diaphragm:
168 Series:
168H Series:
6.9 bar (100 psi)
10.3 bar (150 psi)
Body:
168-1, 168-2,168H-1, and 168H-2:
10.3 bar (150
psi)
168-3, 168-4, 168H-3, and 168H-4:
2.8 bar (40 psi)
Diaphragm Pressure Ranges
168-1 and 168-3: 0.1 to 4.1 bar (2 to 60 psi)
168-2 and 168-4: 0.1 to 2.8 bar (2 to 40 psi)
168H-1 and 168H-3: 3.5 to 10.3 bar (50 to 150 psi)
168H-2 and 168H-4: 2.4 to 6.9 bar (35 to 100 psi)
Diaphragm Pressure Change Between
Switching Points
Minimum
168-1, 168-2, and 168-3:
168-4:
0.5 bar (7 psi)
168H-1, 168H-2, and 168H-3:
168H-4:
1.1 bar (16 psi)
0.7 bar (10 psi)
1.4 bar (20 psi)
Maximum
168-1,168-3:
168-2, 168-4:
168H-1, 168H-3
168H-2, 168H-4:
4.0 bar (58 psi)
2.6 bar (38 psi)
: 6.9 bar (100 psi)
4.5 bar (65 psi)
Proof Test Pressure
All Pressure Retaining Components have been
proof tested per Directive 97/23/EC - Annex 1,
Section 7.4
Operative Temperature Limits
-23.3 to 66°C (-10 to 150°F)
Installation
Only qualified personnel should install or service
a regulator. Regulators should be installed, operated, and maintained in accordance with interna-
tional and applicable codes and regulations, and
Fisher instructions.
If the regulator vents fluid or a leak develops in
the system, it indicates that service is required.
Failure to take the regulator out of service immediately may create a hazardous condition.
Personal injury, equipment damage, or leakage
due to escaping fluid or bursting of pressure-containing parts may result if this regulator is overpressured or is installed where service conditions could exceed the limits given in the Specifications section, or where conditions exceed any
ratings of the adjacent piping or piping connections.
To avoid such injury or damage, provide pressurerelieving or pressure-limiting devices (as required
by the appropriate code, regulation, or standard)
to prevent service conditions from exceeding limits.
Additionally, physical damage to the regulator
could result in personal injury and property damage due to escaping fluid. To avoid such injury
and damage, install the regulator in a safe location.
Clean out all pipelines before installation of the regulator and
check to be sure the regulator has not been damaged or has
collected foreign material during shipping. For NPT bodies, apply
pipe compound to the male pipe threads. For flanged bodies, use
suitable line gaskets and approved piping and bolting practices.
Install the regulator in any position desired, unless otherwise
specified, but be sure flow through the body is in the direction
indicated by the arrow on the body.
Note
It is important that the regulator be installed so that the
vent hole in the spring case is unobstructed at all times.
For outdoor installations, the regulator should be located
away from vehicular traffic and positioned so that water,
ice, and other foreign materials cannot enter the spring
case through the vent. Avoid placing the regulator beneath eaves or downspouts, and be sure it is above the
probable snow level.
Overpressure Protection
The recommended pressure limitations are stamped on the regulator nameplate. Some type of overpressure protection is needed
if the actual inlet pressure exceeds the maximum operating outlet
pressure rating. Overpressure protection should also be provided if the regulator inlet pressure is greater than the safe working
pressure of the downstream equipment.
Regulator operation below the maximum pressure limitations does
not preclude the possibility of damage from external sources or
debris in the line. The regulator should be inspected for damage
after any overpressure condition.
Startup
The regulator is factory set at approximately the midpoint of the
spring range or the pressure requested, so an initial adjustment
may be required to give the desired results. With proper installation completed and relief valves properly adjusted, slowly open
the upstream and downstream shutoff valves.
D100275XENG
1. The pressure/temperature limits in this installation guide and any applicable
standard or code limitation should not be exceeded.
www.FISHERregulators.com

168 Series
Adjustment
To change the outlet pressure, remove the closing cap or loosen
the locknut and turn the adjusting screw clockwise to increase
outlet pressure or counterclockwise to decrease pressure.
Monitor the outlet pressure with a
ment. Replace the closing cap or tighten the locknut to maintain
the desired setting.
Taking Out of Service (Shutdown)
To avoid personal injury resulting from sudden
release of pressure, isolate the regulator from all
pressure before attempting disassembly.
Parts List
168 and 168H Series
Key Description
1 Diaphragm Case
2 Spring Case Assembly
2A Spring Case
2B Spring Case Bushing
3 Diaphragm Piston
4 Diaphragm
5 Machine Screw
6 Stem
7 Range Adjusting Nut
8 Spring
9 Hex Nut
10 Stem Protector
11 Machine Screw
68 Series
Key Description
1 Body
2 Spring Case Assembly
2A Spring Case
2B O-Ring
2C Trip Lever
2D Spring
2E Trip Lever Pin
2F Spacer
3 Rocker Assembly
4 Seat Ring
5 Roller Assembly
6 O-Ring
7 Rocker Pin
8 Machine Screw
9 Machine Screw
10 Nameplate
test gauge during the adjust-
Key Description
12 Machine Screw
13 Hex Nut
14 Nameplate
15 Mounting Bracket
16 Cap Screw
17 Vent Screen
18 Body Assembly
19 Spacer
20 Reset Lever
21 Knob
22 Pin
23 Machine Screw
24 Indicator Tag
DU8794
Figure 1. 68 Series Switching Valve Body Assemblies
DETAIL OF MANUAL RESET
SWITCH FOR USE WITH
EITHER 168 OR 168H SERIES
DU8774-D
168 SERIES
168H SERIES
Figure 2. Switching Valve Constructions
©Fis her Co ntrols Intern ation al, Inc., 2002; All Rights Rese rved
Fisher and Fisher Regulators are marks owned by Fisher Controls International, Inc. The Emerson logo is a trade mark and service mark of Emerson Electric Co.
All other marks are the property of their respective owners.
The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not to be construed as warranties or guarantees, express
or implied, regarding the products or services described herein or their use or applicability. We reserve the right to modify or improve the designs or specifications of such products at any time without notice.
For information, contact Fisher Controls, International:
Within USA (800) 588-5853 – Outside USA (972) 542-0132
France – (33) 23-733-4700
Singapore – (65) 770-8320
Mexico – (52) 57-28-0888
Printed in U.S.A.
www.FISHERregulators.com